250-500cc Jetting Advice Needed

Fouled my first spark plug after about 3 hours of total ride time. I knew I was running rich but bike seemed to run ok so I just rode it. It was only after very slow trail riding that it seemed to give me problems.. It had a empty silencer so I started there and bought some packing along with a new B8RES plug gapped down to .024 as the last one was untouched at .032. I know I shouldn't change more than 1 thing at a time for testing but..

Took carb apart (Mikuni TM)

Airscrew 3/4 out
Main jet 450 (was hard to read the number before 50 but I assume it was a 4)
Pilot 40
6AEJ3-64 needle
Clip in second position

I screwed out the airscrew to 1 and 1/2 out and changed the clip to the highest position (leaner)

Bike has a FMF fatty pipe and a freshly packed silencer. 32:1 motul 710 with 93 octane

Right off the bat it seemed more responsive and stronger in the trails. Opened it up and the top end still seems flat but no stuttering... Thinking up still too rich on the main... There are no jetting guides I have found for this bike since it's fairly old. Any suggestions would be much appreciated

altitude and temperature are key to this question

According to wiki I'm 500ft above sea level and I've been riding in 60-80 degree weather. It's gonna get colder soon though prolly ride in the 40s at the lowest. I stumbled upon a old motorcycle mag review, seems as they changed the needle, slide ect..

http://www.motorcycle.com/manufacturer/trail-test-1996-husqvarna-250-wxcwxe-15944.html

2 pages to that article

http://www.essjayar.com/motorbikes/96EnduroCompare.txt

And another

Good luck and I can't give any real specifics on your issues ...But if you get back to checking your plug colors as a way of jetting the bike, you need to hold the throttle at a specific position to check the jetting at that RPM range .. Meaning, to check the main jet, hold the throttle wide-open at high RPM, kill the engine right there, and then pull the plug and check. Do this for 1\4, 1\2, and other throttle positions.

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As far as no guidelines? Feeding fuel to an engine is pretty basic I'd guess ... Even efi devices today use about the same general ideas\rules as CARB bikes have used forever for feeding fuel into the engine at specific RPM ranges. EFI bikes try to control the fuel flow with software\hardware ... Ain't that cool? More power to software\hardware developers

ive read many times you should jet from the top down, finding the right main is first business. then work on needle settings, then pilot.

Those carbs are brutal to jet. Honestly, there's a magic part that will solve all your problems. Though, it's not cheap, but well worth every penny. LECTRON! You'll never have to worry about jetting again. I had a honda CR250 once that also had a TMX carb. I could never get it good on top without loosing a ton if mid range.

funny but my 93 360 has a Mic TM, IT RUNS GREAT
my dealer had the jetting on a card like in 3X5 index stuff
they can work fine if you know what you are doing
my riding buddy also had a 93 360 and believed all the hype so bought a Keihin, funny but mine ran better
same pipe, he had the better spark arrestor, i was slow to clean my air filter so there are no excuses
find a baseline and jet it, if your wallet is jumping around buy a new carb
if you have the TMX buy a new carb

My carb says TM on the side so I hope that's what I have as I called Halls earlier and ordered a bunch of parts for a ''TM 38.'' I really have no complaints especially after I leaned my airscrew out to 1.5 from full in.. I know you have 100cc on me but what did you end up running on your carb?

Parts are gonna take over a week but I got 430,440 main 37.5,35 pilot 4.0 slide and the leaner 6AEJ1-64 needle coming. At minimum this will be a learning experience.

Other thing that bothers me is my pumps all have 10% ethanol.. So leaning out all aspects of the carb may be a bad thing right?

Chevron has been the best pump premium but we have a different blend here
my friend with the 360 like mine ran race fuel he bought at a supply house, smelled cool if nothing else

many tmx say tm if big letters on the side...got a pic?

Switch from:
B8RES
14mm diameter, 8 temp, resistor, 19mm (3/4") reach, standard electrode

To:
BR8EIX
14mm diameter, resistor, 8 temp, 19mm (3/4") reach, iridium electrode

Do not gap.

I may do that after I finish jetting it correctly. I have a 95 model bike which had all the same jets and needle from the 96 reviews I read, but in 1 review it said new for 96 is a TM38 carb.

I may have screwed up.. I'm going to call Halls tomorrow and make sure the jets slide and needle will interchange. Mine looks like this

http://www.ebay.com/itm/92-1992-hus...ts=Make:Husqvarna&hash=item2338615d4a&vxp=mtr

Tinken ,why do you say no gap on ix? Just put one in my cr and gapped it.

they come pre-gapped.

Mine was gapped to big.

I put in all the jets needle and slide tonight. It's dark and wet now so can't ride but response is better and sounds better just revving. Went from 40 to 35 pilot, 450 to 440 main (have 430 on hand), leaner needle, kept it on the second clip, and 3.5 to 4.0 slide, kept it at 1.5 turns out air screw.

Jetting guides said if it starts cold with no choke pilot is too big which it did before.. To my surprise it started up first kick but died less than 5 seconds later. Pulled choke and it fired right away but rpm was a good amount higher than before so I adjusted that down with idle knob. Gave it a minute on choke than dropped the choke and it idled great with much more response and a higher tone.

Gonna ride tomorrow and test the main and needle clip. Hoping the smaller main will allow it rev higher because right now it feels flat.. Open to any tips with tuning. Thanks

I believe I set the pilot correct with idle being highest starting at 1 turn out with no significant change after that. So Been riding at 1.5 turns out and it runs great but idle hunts around more while riding and will 70% of the time ''hang'' even with the throttle screw turned all the way out. I checked for air leaks spraying carb cleaner around boots ect.. no leaks that I know. And sometimes the throttle sticks and takes a hard rev or two to make it settle (while pulling in the clutch). Not sure if that's jetting or throttle cable.. But as far as the idle hanging and surging. Should since the pilot is set correct should I put the factory richer slide back? Factory richer needle? Change from second to 3rd 4th 5th clip position? Thanks for any help